1. Field of the Invention
The present invention generally relates to systems and methods for managing and controlling a well from the surface, and more particularly relates to a system and method that includes the transmission of downhole well data to the surface, the processing of the well data, and the transmission of commands to downhole controls to manage the well pursuant to the information derived from the downhole well data or other relevant sources. Still more particularly the present invention relates to recompleting an existing well using substantially continuous coilable tubing for the installation of a system and method for managing and controlling the recompleted well.
2. Description of the Related Art
In producing wells, it is desirable to determine if adjustments can be made to maintain or increase production, and if so, to determine if it is desirable to make those adjustments. This is referred to as managing a well and such a well management system with permanently installed sensors to monitor well conditions, and controls which can be adjusted from the surface, may be referred to as a intelligent completion system. In the management of wells, particularly producing wells, it is important to obtain downhole well data to manage and control the production of hydrocarbons over the life of the well. Problems arise in communicating and maintaining downhole sensors and controls which will last throughout the life of the well. Therefore, it is often necessary to monitor the producing well at the surface and to use flow controls located at the surface, such as a choke or other adjustable restriction, to control the flow from the producing formations.
It is expensive to intervene in a well by conventional methods. If adjustments can be made to optimize the well without expensive intervention, then there is an advantage to completing or recompleting the well using a intelligent completion system. This is particularly true of offshore wells where conventional intervention can involve costly equipment and lengthy interruption to supply. Optimization can also extend the economic life of a well.
Petroleum Engineering Services has developed a intelligent completion system referred to as the surface controlled reservoir analysis and management system ("SCRAMS") for providing surface control of downhole production tools in a well. SCRAMS is described in U.S. Pat. No. 5,547,029, hereby incorporated herein by reference. SCRAMS is capable of detecting well conditions and of generating command signals for operating one or more well tools. An electric conductor transmits electric signals and a hydraulic line containing pressurized hydraulic fluid provides the power necessary to operate downhole tools. The well control tool also permits the selective operation of multiple production zones in a producing well.
Intelligent completion systems are sometimes installed in existing wells where production is waning and steps need to be taken to enhance well production, such as for example by reperforating the production zone or perforating a new production zone. Thus it becomes necessary to workover or recomplete the existing producing well and install an intelligent completion management system to monitor and control the well downhole and more particularly to control production between the old and new perforations or production zones. This may become necessary as one or another of the producing zones begins to produce a substantial amount of water as compared to the amount of hydrocarbons being produced. Typically, data acquisition and the sending of commands downhole are performed independently at the surface.
In conventional recompletions, to install an intelligent completion system, the original completion must be removed and the downhole assembly of the intelligent completion system lowered into the borehole of the well on jointed pipe with an umbilical strapped to the outside of the jointed pipe as it is lowered into the borehole from a standard rig. The umbilical includes a bundle of conductors with a wire rope or cable typically covered in a protective sleeve. Often the conductors are housed in conduits with the wire rope protecting the conduits. The bundle may then be strapped to the jointed pipe the assembly is lowered into the well. The conductors are connected to the surface equipment uphole and to the sensors and control devices downhole to transmit data and electrical power. The hydraulic line may be run adjacent to the jointed pipe. The use of jointed pipe and conventional rig equipment for the recompletion is expensive. Also strapping the wireline onto the outside of the jointed pipe is problematic because it introduces the risk of damage to the conductors and subsequent well control problems.
Another disadvantage of conventional systems is that the use of jointed pipe requires the removal of the production tubing from the existing well. The production tubing is not large enough to allow the jointed pipe and umbilical to pass through it and therefore must be removed.
Today, installing the intelligent completion system by conventional means is sufficiently expensive to limit its use in some cases. Further, if the intelligent completion system does not work, the conventional intelligent completion system cannot be easily removed and then reinstalled. To correct a problem, the intelligent completion system must be pulled and a new intelligent completion system installed requiring that the investment be made all over again.
It is known to use steel continuous tubing for completions. Also, steel continuous tubing has been used to install down hole electrical submersible pumps which have a cable extending through the continuous tubing for powering the pump. See for example the paper entitled "Electric Submersible Pump for Subsea Completed Wells" by Sigbjom Sangesland given at Helsinki University of Technology on Nov. 26-27, 1991, hereby incorporated herein by reference. Electrical conductors are shown extending down through steel continuous tubing to provide power to a downhole submersible pump supported on the end of the continuous tubing.
One disadvantage of steel continuous tubing is that the weight of the steel continuous tubing in large diameters and long lengths makes its use impractical. This is particularly true where the steel continuous tubing is several inches in diameter.
One possible solution is the use of a non-metallic continuous tubing such as a continuous tubing made of composite materials. Composite continuous tubing generally is much lighter and more flexible than steel continuous tubing. Composite continuous tubing is still in the developmental stage for possible application in drilling, completion, production, intervention and workover. Composite continuous tubing may also be possibly used for service work, downhole installations, and artificial lift installations. It is also known to extend conductors through the composite tubing. These conductors may be electrical conductors, hydraulic conductors, or optical fibers. See for example U.S. Pat. Nos. 4,256,146; 4,336,415; 4,463,814; 5,172,765; 5,285,008; 5,285,204; 5,769,160; 5,828,003; 5,908,049; 5,913,337; and 5,921,285, all hereby incorporated herein by reference.
The present invention overcomes the deficiencies of the prior art.